JP2549461Y2 - Electric motor with frequency generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an electric motor with a frequency generator (FG), and more particularly to a rotor comprising a stator having a slotted core wound and a multipole magnetized drive magnet. And a frequency generator-equipped electric motor constituted by:

2. Description of the Related Art For example, an electric motor (motor) for rotating a magnetic head in a rotary head type digital audio tape recorder needs to obtain a constant rotation speed. In such a motor, the rotation speed of the rotation of the motor is detected by a frequency generator (FG), and control is performed so that the rotation speed becomes constant.

As the motor for driving the magnetic head, a motor with a cylindrical core may be used in terms of starting torque vibration and the like.

As shown in FIG. 4, a motor with a cylindrical core forms a stator 1 by winding a laminated core, and a rotor magnet 13 having multiple poles magnetized to eight poles as shown in FIG. Is fixed to a rotor yoke 7.

The FG comprises a FG magnet 9 which is multipolarly magnetized with the printed wiring board 10 on which the FG pattern 11 is formed, and is fixed to a peripheral portion of the rotor yoke 7.

The number of pulses of the output FG signal per rotation of the conventional FG rotor 6 was 24 pulses. The number of slots of the core constituting the stator 1 is 12, the number of magnetized poles of the rotor magnet 13 is 8, and the rotor 6, 1
The number of pulses generated per rotation was 12.

Problems to be Solved by the Invention However, in the conventional motor with a frequency generator (FG), the leakage magnetic flux of the rotor and the stator is generated during one rotation of the rotor.
The pulse number of the pulse signal generated by the FG was 12 pulses, which was different from the 24 pulses that the FG should generate during the rotation of the rotor.

FIG. 6 shows an operation waveform diagram of an example of the related art. FIG. 6 (A)
FG pattern detection waveform diagram by FG magnet, Fig. 6
(B) is a detection waveform diagram of the FG pattern by the leakage magnetic flux, and FIG.
FIG. 6C is a composite waveform diagram of the detection waveform by the FG magnet and the detection waveform by the leakage magnetic flux, and FIG. 6D is an FG pulse waveform diagram obtained by shaping the composite waveform into a pulse shape.

The operation waveform diagram of FIG. 6 shows the FG waveform of the motor with a cylindrical core having 8 poles and 12 slots. Therefore, the FG magnet
The number of generated pulses obtained by the FG pattern is 24 per rotation of the rotor, and the number of pulses generated in the FG pattern by the leakage magnetic flux of the rotor magnet is 12 per rotation of the rotor.

Therefore, as shown in FIGS. 6A and 6B, the period of the detection waveform of the FG pattern due to the leakage magnetic flux is determined by the FG magnet.
This is twice the period of the detected waveform of the FG pattern. Therefore, when these are combined, a combined waveform as shown in FIG. 6C is obtained.

By setting the center voltage of the composite waveform of FIG. 6C as a threshold and setting the high level if the composite waveform is larger than the threshold, and setting the low level if the composite waveform is smaller than the threshold, the waveform is shaped into a pulse by FIG. A pulse-like waveform as shown in (D) is obtained.

As shown in FIG. 6 (A), the pulse waveform in FIG. 6 (D) has a constant rotation of the rotor and the FG magnet has a constant FG pattern and the detected waveform is constant. As a result of synthesizing the waveforms having different periods as described above, the waveform becomes a distorted waveform as shown in FIG. 6C. Since the waveform is shaped into a pulse, the waveform has different periods T1 and T2.

As described above, conventionally, since the output pulse signal of the FG is obtained by superimposing the leakage magnetic flux, the output signal of the FG is distorted, so that an accurate FG signal cannot be obtained and accurate control cannot be performed. There was a point.

The present invention has been made in view of the above points, and an accurate FG
An object of the present invention is to provide a motor with a frequency generator from which a signal can be obtained.

Means for Solving the Problems According to the present invention, a rotor composed of a multi-pole magnetized rotor magnet is provided facing a stator having a core having a slot and a winding wound thereon, and the rotation speed of the rotor is detected by a frequency generator. In a motor with a frequency generator that rotates a rotor by controlling a signal supplied to a winding constituting a stator, the number of pulses to be detected by the frequency generator per rotation of the rotor and the number of pulses of the stator and the rotor The number of slots of the core constituting the stator and the number of magnetized poles of the rotor magnet constituting the rotor are set so that the number of pulses detected by the frequency generator per rotation of the rotor by the leakage magnetic flux is the same. Set it.

The number of slots of the core forming the stator and the number of magnetization of the rotor magnet forming the rotor are determined by the number of pulses per rotation of the rotor and the frequency generated by the frequency generator when the frequency generator detects leakage flux of the stator and the rotor. The number of pulses to be detected per rotation is set to be the same.

Therefore, the output of the frequency generator is obtained by superimposing a pulse signal of the number of pulses to be detected per one rotation of the rotor and a pulse signal of the same number of pulses due to the leakage magnetic flux.
Therefore, the influence of the pulse signal due to the leakage magnetic flux does not occur.

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a plan view and a side view of a main part of one embodiment of the present invention, and FIG. 3 is another essential view of one embodiment of the present invention. FIG. 3 shows a plan view and a side view of the section.

The motor (electric motor) of the present embodiment is a cylindrical motor with a laminated iron core that detects the rotor magnetic pole using a Hall element, detects the rotational position of the rotor, and controls the current of the stator coil to rotate the rotor. High starting torque and low noise.

The stator 1 has a configuration in which a winding 3 is applied to a core 2 formed by laminating metal plates as shown in FIG. Core 2 is winding 3
Has 12 slots (grooves) 4 for winding the.

The winding portion of the winding 3 of the core 2 has a T-shape from the center of rotation toward the outer periphery, and the winding 3 is wound around this portion. The core 2 is fixed to the holder 5.

The rotor 6 has a rotor magnet 8 fixed to a rotor yoke 7. The rotor magnet 8 has a cylindrical shape and is magnetized to 16 poles as shown in FIG. The rotor magnet 8 is fixed by an adhesive inside the rotor yoke 7 forming a magnetic circuit. The rotor 6 is rotatably held as if it were placed over the stator 1 from above.

An annular FG magnet 9 is fixed to a peripheral portion of the rotor yoke 7. The FG magnet 9 is magnetized to 48 poles.

A printed circuit board 10 on which a control circuit is formed is fixed to the holder 5 to which the stator 1 is fixed.
An FG pattern 11 for generating an FG signal is formed in a circular shape on a portion of the printed wiring board 10 facing the FG magnet 9.

When the rotor 6 rotates, the FG magnet 9 rotates. FG
Due to the rotation of the magnet 9, the magnetic flux of the FG magnet 9 becomes FG
When crossing the pattern 11, a pulse signal is generated. At this time, the FG pattern 11 is formed such that a pulse signal of 24 pulses is output in one rotation of the rotor 6 with respect to the magnetization of the FG magnet 9 with 48 poles.

The printed wiring board 10 is connected to an external circuit by a connection cord 12, outputs a control signal such as an FG signal to the external circuit, and supplies a motor drive signal from the external circuit.

The printed wiring board 10 is connected to the winding 3 wound around the core 2 and supplies a signal to the winding 3 according to a signal from an external circuit. Further, a Hall element 13 is provided on the printed wiring board 10, and a rotation signal of the rotor 6 detected by the Hall element 13 is supplied to the winding 3 where the rotation position of the rotor 6 is detected by the Hall element 13. Controlled by position.

When the rotor 6 rotates, the magnetic circuit formed by the core 2, the rotor yoke 7, and the rotor magnet 9 changes with time. In addition to the magnetic flux from the FG magnet 9, the leakage magnetic flux jumps into the FG pattern 11.
A pulse signal is generated in pattern 11. At this time, the number of pulses of the pulse signal generated in the FG pattern 11 per rotation of the rotor 6 is determined by the number of poles of the rotor magnet 8 and the number of slots of the core 2, and has a relationship as shown in Table 1.

In this embodiment, since the number of slots of the core 2 is 12 and the number of poles of the rotor magnet 8 is 16, the FG pattern 11 has the rotor 6 and the number of pulses generated per rotation of 24. It is the same as the number of pulses of the generated pulse signal. Since the FG signal is obtained by superimposing these pulse signals, the pulse signal generated in the FG pattern 11 by the leakage magnetic flux does not affect the pulse signal generated in the FG pattern 11 by the FG magnet 9.

FIG. 7 shows an operation waveform diagram of one embodiment of the present invention. FIG.
(A) is a detection waveform diagram of the FG pattern by the FG magnet,
FIG. 7 (B) is a detection waveform diagram of the FG pattern by the leakage magnetic flux,
FIG. 7C is a composite waveform diagram of a detection waveform by the FG magnet and a detection waveform by the leakage magnetic flux, and FIG. 7D is a FG pulse waveform diagram obtained by shaping the composite waveform into a pulse shape.

The operation waveform diagram of FIG. 7 shows an FG waveform of a motor with a cylindrical core having 16 poles and 12 slots. Therefore, the number of pulses generated in the FG pattern by the leakage magnetic flux of the rotor magnet is 24 per rotation.

If the detected waveform of the FG pattern by the FG magnet shown in FIG. 7A is the same as the detected waveform of the FG pattern by the leakage magnetic flux shown in FIG. 7B, the detected waveform of the FG magnet shown in FIG. Even if the phase of the leakage magnetic flux detection waveform shown in FIG. 7 (B) is shifted, the combined waveform does not distort as only the phase and amplitude are changed as a whole as shown in FIG. 7 (C). FIG. 7A shows the detection waveform of the FG magnet and FIG.
Even if the detection waveform of the leakage magnetic flux shown in FIG. 7B is completely out of phase, the amplitude of the detection signal of the FG magnet in FIG. Since it is sufficiently large, a detection signal can be obtained.

Therefore, the waveform of FIG. 7C is compared with the center level, and if it is higher than the center level, it is set to the high level, and if it is lower than the center level, it is set to the low level. Such a pulse-like waveform is obtained. In the pulse waveform of FIG. 7D, since the composite waveform of FIG. 7C is not distorted, if the rotation of the rotor is constant, the frequency becomes constant in the composite waveform, and the constant period T0
Can be obtained.

Therefore, even if the phases of the FG magnet and the rotor magnet are shifted, the FG signal obtained by the FG pattern is not distorted, and a desired FG pulse can always be obtained. In this embodiment, the FG magnet 9 is magnetized with 48 poles, the rotor 6 generates 24 pulses in the FG pattern 11 per rotation, and accordingly, the number of slots is set to 12, and the number of rotor magnet poles is set to 16. The numerical values may be determined so that the number of pulses generated per one rotation of the FG signal to be output and the number of pulses generated by the leakage magnetic flux are the same.

Effects of the Invention As described above, according to the present invention, the number of slots of the core constituting the stator and the number of magnetized poles of the rotor magnet constituting the rotor are determined by the number of pulses of the pulse signal generated by the stator and the rotor by the magnetic flux leaking from the frequency generator. And the number of pulses of the pulse signal to be generated in the frequency generator are set to be the same, so that the output of the frequency generator is not affected by the leakage flux from the stator and rotor, and the FG signal without distortion is generated. It has such features that it can be controlled accurately by the FG signal.

[Brief description of the drawings]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a plan view and a side view of a main part of the present invention, FIG. 3 is a plan view and a side view of another main part of the present invention, FIG. The figure is a side view of an example of the related art.
FIG. 6 is a plan view and a side view of a main part of a conventional example, FIG. 6 is an operation waveform diagram of an example of the related art, and FIG. 7 is an operation waveform diagram of an embodiment of the present invention. 1 ... stator, 2 ... core, 3 ... winding, 4 ... slot, 6 ... rotor, 8 ... rotor magnet, 9 ...
FG magnet, 11 …… FG pattern.

Claims (1)

(57) [Scope of request for utility model registration] A rotor comprising a multi-polarized rotor magnet is provided opposite to a stator having a core having a slot and a winding, and the rotation speed of the rotor is detected by a frequency generator. An electric motor with a frequency generator for controlling a signal supplied to a wire to rotate the rotor, wherein the frequency generator detects the number of pulses to be detected per rotation of the rotor and the frequency generator sets the stator to rotate per rotation of the rotor. And a frequency set by setting the number of slots of the core constituting the stator and the number of magnetized poles of the rotor magnet constituting the rotor so that the number of pulses obtained by detecting the leakage magnetic flux of the rotor becomes the same. Electric motor with generator.